Radio communication networks often use information representing certain characteristics or parameters of different parts of the network. For example, some mobile radio location systems operate by using radio measurements to estimate the location of mobile terminals relative to the known locations of the radio network access points. For the special case of cellular mobile phone location systems these access points are the cells.
A location system which estimates the location of a mobile terminal relative to one or more radio network access points requires knowledge of the relevant characteristics of those access points. For example, in a coarse cell identifier based mobile cellular location system, the relevant characteristics typically include the unique identifier for the cell and the geographical coordinates at which the cell is situated.
More accurate systems such as those which also incorporate radio signal measurements in the calculation process require additional configuration information. This typically includes transmitted power, antenna gain and antenna orientation.
The performance of such location systems is strongly dependent on the integrity of the database containing this network configuration information. This dependence increases in systems promising greater levels of spatial resolution or accuracy. In an ideal world, the configuration of the cellular network will match the network database. Experience has shown however, that typically the configuration information is poorly maintained, distributed across multiple databases and exhibits many errors.
Reasons for discrepancies between the supplied database and actual configuration may lie with the network database or with the network configuration or both. The database may be at fault due to errors such as typographical errors, especially the transposition of numbers, during data entry; problems with the process used to collect and collate the network data; and failure to propagate network configuration changes to the database. Conversely the network configuration may not be as intended due to errors such as typographical errors when entering configuration details and failure to configure one or more planned network changes.
A further problem for operators is that the network configuration is not static. Opportunities for inconsistencies to arise between the network database and deployed configuration occur throughout the life of the network. The network configuration changes when sites are added to increase capacity and/or coverage. Changes also occur when cells are decommissioned. When mobile cells (referred to as Cells-On-Wheels) are setup to support the capacity increases required to support events such as significant sporting events and outdoor music concerts. These temporary additions and deletions to the network can last for hours and in some cases days. The configuration may change temporarily when there is a cell not operating due to scheduled maintenance, equipment failure, or power failure. The network also changes when technicians retune the network to improve performance or to adapt to changes due to reasons discussed above.
Network database errors lead to corresponding errors in the operation of the location-based system and associated services, in some cases leading to unacceptable service quality for subscribers. Network operators have no means of validating that the network is configured as planned other than to perform drive tests around the network with radio monitoring equipment. The cost of updating the database so that it is continually up-to-date represents a significant operational burden for the service provider.
Operators of mobile radio networks change the configuration of and add to the network for reasons such as performance improvement and capacity increases. When these changes are made all associated location systems need to be updated with the changed configuration. Failure to do so will degrade the performance of the location system, possibly to the point where the location system is ineffective.
It is an object of the present invention to facilitate the correction and maintenance of mobile network configuration information.